Hernández-Molina Ricardo, Fernández-Zacarías Francisco, Benavente-Fernández Isabel, Jiménez-Gómez Gema, Lubián-López Simón
Acoustic Engineering Laboratory, CASEM, University of Cádiz, Cádiz, Spain.
Neonatal Unit, Puerta del Mar University Hospital, Cádiz, Spain.
Noise Health. 2017 Jan-Feb;19(86):20-23. doi: 10.4103/1463-1741.199237.
One of the problems that the delivery of continuous positive airway pressure (CPAP) via a helmet poses is the generation of noise. The objective of our study was to assess the effect that the use of filter has on sound pressure levels generated by the delivery of positive airway pressure at different gas flow rates.
Sound pressure levels generated by neonatal helmet CPAP delivery were measured at different gas flows (20, 30, and 40 l/min) with and without a breathing filter. Noise intensity was measured by installing microphones in the inner ear of dummy heads wearing helmets.
The sound pressure level increased by 38% at a gas flow of 40 l/min, as compared to a gas flow of 20 l/min {74 dBA [interquartile range (IQR) 2,2] vs 52 dBA (IQR 5,9), respectively}. Using the breathing filter as a diffuser has a variety of effects on sound pressure levels according to the gas flow rate.
The intensity of the noise generated by helmet delivery of positive airway pressure depends on the type of helmet used, gas flow, and use or not of a diffuser filter. Breathing filters with gas flows over 30 l/min might not be recommended since they would not attenuate but will rather amplify sound pressure.
通过头盔输送持续气道正压通气（CPAP）存在的问题之一是产生噪音。我们研究的目的是评估使用过滤器对不同气体流速下输送正压气道压力所产生的声压级的影响。
在有和没有呼吸过滤器的情况下，于不同气体流速（20、30和40升/分钟）下测量新生儿头盔式CPAP输送产生的声压级。通过在佩戴头盔的模拟人头内耳处安装麦克风来测量噪音强度。
与20升/分钟的气体流速相比，40升/分钟的气体流速下声压级增加了38%{分别为74分贝[四分位间距（IQR）2,2]和52分贝（IQR 5,9）}。根据气体流速的不同，将呼吸过滤器用作扩散器对声压级有多种影响。
头盔输送正压气道压力产生的噪音强度取决于所使用头盔的类型、气体流速以及是否使用扩散器过滤器。不建议使用气体流速超过30升/分钟的呼吸过滤器，因为它们不会减弱反而会放大声压。
